Belief in the Hereafter is one of the six pillars of Islamic belief required of a Muslim in order to complete his faith. The Prophet, sallallaahu ‘alaihi wa sallam (may Allah exalt his mention), informed us about events of the Ghayb (those beyond human perception) which will occur after death. This fundamental belief is only completed when one has firm faith in his heart in all those matters about which the Prophet, sallallaahu ‘alaihi wa sallam, informed us.
Ahlus-Sunnah Wal-Jamaa’ah (mainstream Muslims) believe in all of these events, whereas the people of innovation refuse to accept events such as the questioning in the grave, the bliss and the trials of the grave, the punishment in the grave, the passing over the Siraat (the Bridge set over Hell), and the setting of the scales. The reason for their denial is that, in their estimation, these matters cannot be proven by mere intellect. Since they consider their intellect to be the judge over everything, they do not believe in matters which are beyond their comprehension.
Materialists refuse to believe in anything which they do not feel. Our answer to this attitude is that our inability to sense the existence of certain things does not justify our denial of the very existence of those things. Certitude through news from an authentic person is as good as the certitude by seeing and feeling. Since the honesty of Prophet Muhammad, sallallaahu ‘alaihi wa sallam, in conveying the Divine Message revealed to him has been established for us, we-believers- firmly believe in everything he, sallallaahu ‘alaihi wa sallam, told about the unseen, including the Hereafter. Belief in the hereafter entails the following:
(A) Belief in Events of the Grave
Ahlus-Sunnah Wal-Jamaa’ah believe in the trial of the grave. The Arabic word for trial is ‘Fitnah’, which linguistically means to place gold in fire in order to remove its impurities; this word was thus later used in the sense of testing and trying.
The Qur’anic evidence concerning this issue is in the following verse in which Almighty Allah describes the punishment of the people of Fir’awn (Pharaoh); He, the Most Exalted, Says (what means): “The Fire: they are exposed to it morning and evening. And the Day the Hour appears [it will be said]: ‘Make the people of Pharaoh enter the severest punishment.’” [Qur’an 40:46]
Also, the Prophet, sallallaahu ‘alaihi wa sallam, said: “The grave is either a garden from the Gardens of Paradise, or a pit from the pits of Hell.” [At-Tirmithi]
(B) Events of the Day of Judgment
After the duration of this earth is over, Allah will command Israafeel [the Angel in charge of blowing the Trumpet] to blow it. At the first blowing, all the inhabitants of the heavens and the earth will fall unconscious, except those for whom Allah Wills otherwise. Then, the earth will be flattened and the mountains will be made into floating sand dunes. In short, everything will occur that Allah has informed us about in His book, especially in chapters 81 and 82 of the Noble Qur’an.
Then Allah will command the skies to pour rain. This rain will resemble the sperm of men. People will then be resurrected from their graves. This process will start from their vertebral column. The entire body of a person decays after his death except the lower end of the vertebral column. This process of resurrection will continue until they are transformed back into their original shape and bodies. Allah will then command Israafeel to blow the Trumpet for the second time, upon which people will rise from their graves alive. The disbelievers and the hypocrites will then be regretful and will say (what means): “…Woe to us! Who has raised us up from our sleeping place?” [Qur’an: 36:52] Whereas the believers will say (what means): “…This is what the Most Merciful had promised, and the Messengers spoke the truth.” [Qur’an 36:52]
Then angels will drive all of them naked, uncircumcised, and barefooted to the place of Hashr (Gathering).
The first one to be dressed on that Day will be Prophet Ibraaheem, may Allah exalt his mention. At the place of Gathering, the sun will descend close to the heads of people, and their sweat will engulf them. It will be up to the ankles of some of them, up to the knees of others, up to the chests of others, and up to the necks of others. The level of their sweat will be in accordance with their deeds.
Some people on that Day will be sheltered by the shade of the Throne of Allah. When the conditions become unbearable for people, and the despair increases greatly, people will ask Allah to allow His messengers and prophets to intercede on their behalf and save them from their distress. Every messenger and prophet will direct the people to the prophet who came after him, until they come to our Prophet Muhammad, sallallaahu ‘alaihi wa sallam. He will respond by saying that he is the appropriate person for it. He will intercede for them, which will result in the beginning of Judgment.
(C) The Balances
The balances will then be erected, and the deeds will be weighed. These balances will be real and will have pans and needles. Allah, the Exalted and Glorified, will give the deeds of the creatures a material existence that will have weight. The good deeds will be placed in one pan and the evil deeds in the other, as Allah informs us in the Qur’an by Saying (what means): “And We shall set up balances of justice on the Day of Resurrection, then none will be dealt with unjustly in anything. And if there be the weight of a mustard seed, We will bring it. And Sufficient are We to take account.” [Qur’an 21:47]
(D) The Records
This will be followed by the disclosure of the record of deeds. He who will receive his record in his right hand will have an easy reckoning. He will return to his family in happiness. However, he who will receive his record from behind and in his left hand will seek death on that Day, as he will be thrust into the Hellfire. He will be full of regrets on that Day and will wish that he were not handed his record or that he had not known about it. Allah Says (what means): “Then as for him who is given his record in his right hand. He will be judged with an easy account. And return to his people in happiness. But as for he who is given his record behind his back. He will cry out for destruction. And [enter to] burn in a Blaze.” [Qur’an 84:7-12]
All the events that are bound to occur after death and on the Last Day, like reward and punishment, Paradise and Hell, the Reckoning and other events are mentioned in detail in the Divine revelations and in narrations from the prophets. They are also available in the knowledge which the Prophet, sallallaahu ‘alaihi wa sallam, has left us as his inheritance; whoever wishes to seek it will find it.

Article source: http://www.islamweb.net/emainpage/

Special places where one’s supplication is accepted
Inside the Ka’aba: Usamah bin Zaid, radhiallahu ‘anhu, narrated that the Prophet, sallallaahu ‘alaihi wa sallam, when he entered the Ka’aba, made Du’a (supplication) to Allah at all its sides [Muslim].
In another hadith, Abdullah bin Umar said, “I saw Allah’s Messenger entering the Ka’aba. He, Usamah bin Zaid, Bilal and ‘Uthman bin Talha and they (locked the door) on themselves. So when they opened it, I was the first enter and I met Bilal and asked him, “Did Allah’s Messenger pray in it?” He said, ‘Yes’, he prayed between the two Yamani pillars” [Bukhari and Muslim].
However, it might be difficult for many of people to enter the Ka’aba. In such a situation, it is sufficient for a person to make Du’a inside the wall which is surrounding the Ka’aba from one side as this is considered a part of the Ka’aba. The evidence is in the hadith where ‘Aishah, radhiallahu ‘anha, asked Allah’s Messenger about the Jidar (wall) – ‘Is it part of the Ka’aba? He said, ‘Yes’. She said, ‘Why did they not enter it into the Ka’aba?’ He said. ‘Your people lacked sufficient funding’ [Bukhari and Muslim].
At Safa and Marwah: Jabir narrated in his lengthy hadith about the pilgrimage (Haj) of the Messenger of Allah ‘....then he walked out from the door heading towards As-Safa, and when he got closer to the Safa, he read “Verily, As-Safa and Al-Marwah are of the symbols of Allah” {Al-Baqarah, 158} “I begin with that which Allah began with” so he began with As-Safa and went up on it till he sighted the Ka’aba, he faced the Qiblah and then proclaimed the oneness of Allah, made Takbeer and said, “La Ilaha Illallah Wahdahu La Shareeka Lah. Lahul-Mulk wa Lahul-Hamd, Wa-Huwa ‘Ala Kulli Shay-in Qadeer. La Ilaha Illallahu Whadah, Anajaza Wa’dah, Wa Nasara ‘Abdah, Wa Hazamal Ahzaaba Wahdah” then he made Du’a between the two, repeating what he said three times..’ In the hadith it is also mentioned that ‘he did the same actions at Al-Marwah as he did at As-Safaa’ [Muslim]. Therefore, it is a Sunnah to make Du’a to Allah at As-Safa and at Al-Marwah during ‘Umrah or Haj as these are counted among the places where Du’a is accepted.
At Arafah: During the Haj, and particularly on the day of ‘Arafah, one must try to make Du’a to Allah subhanahu wa ta’ala as much as he can because a Du’a made on this day is the best Du’a and it is more likely to be accepted as explained in the following hadith. ‘Amru bin Shu’aib narrated from his father who, in turn, narrated from his father that the Prophet, sallallaahu ‘alaihi wa sallam said, “The best Du’a is the Du’a (made) on the day of ‘Arafah” [Tirmithi]

The people from whom Du’a is accepted
Anyone who abides by the conditions of Du’a, refrains from the reasons of its rejection, implements its manners and seeks the times and places of acceptance will be among those whose Du’a will be accepted. The Sunnah of the Prophet, sallallaahu ‘alaihi wa sallam, has also shown us specific types of people whose Du’a are especially accepted by Allah subhanahu wa ta’ala.
A person’s Du’a for his Muslim brother: A Muslim must always try to remember his brothers during Du’a because such a Du’a is accepted by Allah. Whatever we ask for out brother, we will be granted likewise. Um-Ad-Dardaa narrated that the Prophet used to say, “A Muslim’s Du’a his brother in his absence is accepted. There is an angel (assigned) close to his head, whenever he supplicates for his brother that which is good, the assigned angel says, Ameen, you will be granted similarly” [Muslim]
Du’a of an oppressed person: On many occasions, the Prophet, sallallaahu ‘alaihi wa sallam, used to warn his companions from the Du’a of an oppressed person as it will certainly by answered. An example of this is the incident when Allah’s Messenger sent Mu’adh bin Jabal to Yemen. He gave him many instructions among which he said “And beware of an oppressed person’s Du’a for there is no shield between it and Allah” [Bukhari].
A father’s Du’a against his child: When in anger, parents must avoid making Du’a against their children as it might be answered, and that they will regret the Du’a later. A father’s Du’a for or against his children is answered as was mentioned by the Prophet, sallallaahu ‘alaihi wa sallam, in the hadith narrated by Abu Hurairah “Three (types) of Du’a are answered, without doubt – an oppressed person’s Du’a, a travelling person’s Du’a and a father’s Du’a for his son” [Tirmithi, Abu Dawood]. In another narration collected by Ahmed and Tirmithi, the Prophet said “a father’s Du’a against his son”.
A fasting person’s Du’a: Abu Hurairah narrated that Allah’s Messenger said, “Three (types) of Du’a are not rejected – a fasting person’s till he breaks fast, a just ruler’s and an oppressed person’s...” [Tirmithi]. In another collected by Tirmithi, it has been reported that when a person invokes Allah when he is about to break his fast, his invocation is not rejected.
A pious child’s Du’a for the deceased parents: Children remain a benefit even when a person has passed away. When they make Du’a to Allah requesting pardon for their deceased parents, their Du’a is accepted. The one whose children forget after death, is certainly a loser. Abu Hurairah narrated that Allah’s Messenger said, “When a person dies, all rewards from deeds are terminated except from three – a continuing charity, (‘Ilm) knowledge from which benefit is (still) gained, and a pious child who is making Du’a for him” [Muslim].

Article source: htp://www.islamweb.net/emainpage/

The one who commands good and forbids evil
There are some important qualities that must be satisfied in the person who commands good and forbids evil. Ibn Taymiyyah (rahimahullah) said:
“An intention associated with a deed is praiseworthy, acceptable to Allah and rewardable by Him, if that deed is done for Allah. And a deed is praiseworthy and righteous if it is commanded to do by Allah. Since this is the definition of every righteous deed, then the one commanding good and forbidding evil must satisfy it in himself. Furthermore, his deed of commanding good and forbidding evil will not be righteous unless he bases it on knowledge and understanding... For, it is necessary to know the situation of the person being commanded and forbidden.

Knowledge
This knowledge is defined by Ibn Taymiyyah (rahimahullah) as follows:
“Knowledge is that with which Allah sent His Messenger (sallallaahu ‘alaihi wa sallam) and it is the authority that Allah mentioned:
Indeed those who dispute about Allah’s ayaat without any authority given to them, there is nothing in their chests except pride. [Ghaafir 40:56]
So if anyone speaks in matters of religion with other than what Allah sent His Messenger (sallallaahu ‘alaihi wa sallam), he would be speaking without knowledge. Indeed, he whom the Shaytaan leads, he will misguide him from the truth and will guide him instead to a severe chastisement. But as for him who submits to Allah’s Religion, he will be serving Allah with certainty.”

Gentleness
Ibn Taymiyyah (rahimahullah) said:
“One of the righteous qualities in commanding good and forbidding evil is for it to be done according to as-siraatul-mustaqeem (the Straight Path). This is the best way to reach the goal. Accordingly, gentleness is essential, as the Prophet (sallallaahu ‘alaihi wa sallam) said:
“Gentleness does not exist in anything but it is beautified by it; and harshness does not exist in anything but it is marred by it.” [Muslim]
And he (sallallaahu ‘alaihi wa sallam) said:
“Indeed Allah is Gentle, He loves gentleness in all matters. He gives, through gentleness, what he will not give through harshness.” [Muslim]

Patience
Ibn Taymiyyah then said:
“It is also necessary for the one commanding good and forbidding evil to be tolerant, and to be patient with offences. For he will surely suffer offences; so if he does not tolerate and forebear, he would do more harm than good, as Luqmaan said to is son:
And command good and forbid evil, and be patient with whatever afflicts you; indeed this is the firmness required for matters. [Luqman 31:17]
For this reason Allah commanded His messengers (who were the leaders in commanding good and forbidding evil) with patience. He (sallallaahu ‘alaihi wa sallam) said:
“O you who are wrapped up (Muhammad)! Arise and warn (people). Magnify you Lord, purify your clothes, shun atrocities, do not seek increase for yourself, and have patience for your Lord.” [al-Muddath-thir 74 1- 7]
So He opened these ayaat announcing the Message of Muhammad to the creation with a command to warn them, and ended them by commanding patience. Since warning is in itself commanding good and forbidding evil, it is deduced that it must be followed with patience.
And He said:
And have patience with what they say; and leave them with noble dignity. [Al-Muzzammil 73:10]
And:
Therefore patiently persevere, as did (all) messengers of firm resolution. [Al-Ahqaaf 46:35]
And be patient, and your patience is not but from Allah. [An-Nahl 16:127]
And:
And be patient, for indeed Allah will not waste the reward of the muhsinoon (those who do their deeds in the best way). [Hud 11:115]

Conclusion
And Ibn Taymiyyah (rahimahullah) said:
“Thus there are three essential qualities that must be present in the person who commands good and forbids evil: Knowledge, Gentleness, Patience
“Knowledge must precede the command or prohibition; gentleness must consort it, and patience must follow it.
Surely each of these three would normally be present in a person in all such situations, as is reported from some of the salaf:
“‘None is to command good and forbid evil unless he understands what he is commanding and forbidding, and is patient in his commanding and forbidding.’”
Elaboration on the principle of knowledge and its significance for commanding good and forbidding evil, Ibn Taymiyyah said:
“Allah ordered us to command good and forbid evil. But commanding something must be preceded by knowing it; one who does not know the good will be unable to command it. And prohibiting evil must be preceded by knowing it; one who does not know it will not be able to prohibit it.
“Also, Allah obliged us to do good and avoid evil. Surely loving a good thing and doing it, and hating a wicked thing and avoiding it cannot occur except after knowing these things. This knowledge is needed in order for the intent of doing good and forbidding evil to be correct, because the intention must be proceeded by knowledge. One cannot expect a person who does not know a particular thing to develop love or hatred for it, nor an intention to do or avoid it.
“Indeed, doing something and commanding it implies a detailed knowledge about it, enabling one to do it, and to command it, if needed, in a clear manner.”
* Excerpted from the book The Fundamentals of Commanding Good and Forbidding Evil according to Shaykhul-Islam Ibn Taymiyyah